A box casing

ABSTRACT

The invention relates to a box casing (1), such as a box, having four lateral walls (2). The box casing (1) has a reinforcing corner element (5) in each inner corner thereof. Each corner element (5) has two stiff plate-like parts (6) interconnected by a flexible portion (7) and is configured to extend along a corner from a bottom region to a top region of the casing (1). The box casing (1) further has an arrangement configured to hold the corner elements (5) in the respective inner corners in a state of use of the box casing (1). The arrangement comprises members (10) folded from the top (11) and bottom borders of the casing (1) into the inner space (17) thereof defined by the walls (2) and towards an inner surface (18) of an associated wall (2) to trap a said stiff plate-like corner element part (6) between this member (10) and said inner surface (18).

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a box casing according to the preamble of claim 1.

The invention relates especially to such a box casing which is intended to be used within the field of commercial logistics, such as a box, pallet collar or similar construction to be used for storing goods in a warehouse, for transport of components from a subcontractor to a manufacturer or for transport of end products from a manufacturer to a store.

BACKGROUND ART

A conventional box casing of this type is for instance a regular transport box made of corrugated paper, which consists of four lateral walls, a bottom and a lid. Important characteristics of such box casings are for instance low production costs, low weight, and good wear resistance, recyclability and stacking ability.

Regular corrugated boxes of this type are produced to a low cost, has low weight and are easy to recycle. However, these are not suited for containing heavy loads or for being stacked on top of each other. They also have bad wear resistance which makes them risky to use for transporting expensive and fragile goods. Heavy, fragile or expensive goods are therefore often transported in wooden or plastic boxes. However, these are much more expensive to produce and has a significant weight making them difficult to handle and resulting in higher fuel costs during transport.

A solution for increasing the wear resistance and stacking ability of regular corrugated boxes is presented in the document U.S. Pat. No. 3,368,736, which discloses a box casing of the type defined in the introduction already known. This solution consists of simply providing each corner of a corrugated box with a reinforcing corner element, which are secured to the lateral walls of the box by staples or adhesive, on the outside (FIG. 5) or inside (FIG. 3) of the box.

There is a constant strive for improving box casings of this type, for instance with respect to the characteristics mentioned above, due to the ever increasing need for transportation of goods and the fact that logistics becomes an ever more important part of the value chain of a product.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a box casing of the type defined in the introduction being improved in at least some aspect with respect to such box casings already known, for example through said document.

This object is according to the invention obtained by providing such a box casing which is characterized in that said arrangement comprises for each lateral wall associated with a corner element, for each corner element, at the bottom region as well as at the top region of the wall a member attached to the wall and folded into the inner space of the casing defined by the walls and towards an inner surface of the wall to trap said stiff plate-like corner element part between this member and said inner surface. Such an arrangement enables a simple mounting of the corner elements in the inner corners of the box casing, without the need for any staple or glue gun. Hence, a strong box casing which has few separate components and materials is provided, which makes it cost-efficient and environmentally friendly to produce.

According to an embodiment of the invention each said member is an integral part of the respective wall to be folded into the inner space of the casing from a top border or a bottom border of the casing. Such members reinforce the box casing at the top and bottom borders thereof, which for instance improves the stacking ability.

According to another embodiment of the invention each said member has a first section folded to be arranged between an inner wall surface and a respective stiff plate-like corner element part and a second section folded towards said inner wall surface to hold said corner element part trapped between this second section and said inner surface so as to lock said first section of the member between the inner wall surface and the corner element part and by that lock the member in a state of trapping the corner element part. Such members provide an effective retaining of the corner elements in the inner corners of the box casing, as well as a great reinforcement of the box casing at the top and bottom borders thereof due to the double-walled (first and second section) structure and secure locking of the members.

According to another embodiment of the invention each said member comprises a third section folded from a top border or a bottom border of the casing inwardly by 90° or substantially 90° to form a stop to prevent said stiff plate-like corner element part to escape in the direction of the extension of the corner, and the second section is folded from the third section to extend in said inner space of the casing substantially in parallel with said inner wall surface.

According to another embodiment of the invention the extension of said third section inwardly is approximately the same as the thickness of a said stiff plate-like corner element part.

According to another embodiment of the invention said first and second sections of each member are interconnected by a fourth section folded from said second section towards said inner wall surface and from which said first section is folded to extend oppositely to the second section along said inner wall surface towards said top border or bottom border of the casing.

According to another embodiment of the invention said third and fourth sections of each said member have substantially the same width as seen in a direction perpendicularly to the respective inner wall surface.

According to another embodiment of the invention the first sections of all said members at the top and bottom border of the casing, respectively, are formed together in one piece configured to, in said state of use, be folded in the corners of the box casing to extend along the entire inner circumference thereof. This structure of the first sections imply a great reinforcement of the box casing along the entire top and bottom borders thereof and a very reliable retaining of the corner elements in the inner corners of the box casing, as no member may be unfolded to release a corner element without all members being unfolded at the same time. Thus, each single corner element obstruct releasing of every member from the state of trapping a corner element part.

According to another embodiment of the invention each member is a flap extending from the top or bottom border of the casing and having a plurality of mutually foldable plate-like sections.

According to another embodiment of the invention each member is configured to extend along the entire, or substantially the entire, length of a respective lateral wall, from one inner corner of the casing to another, and by that to trap a said stiff plate-like corner element part by each of two end portions of the member in said state of use of the box casing. Such members imply a great reinforcement of the box casing along the entire top and bottom borders thereof as well as a steady retaining of the corner elements in the inner corners of the box casing.

According to another embodiment of the invention each corner element comprises an elongated sheet of a flexible material and the two stiff plate-like parts are secured to the sheet by an adhesive at a distance to each other on opposite sides of a longitudinal central section of the sheet, which central section constitutes the flexible portion of the corner element. This configuration of the corner elements enable a simple and cost-effective production thereof while providing corner elements that are durable without fastening means in the form of nails, screws, stapler pins or similar.

According to another embodiment of the invention each corner element is configured to be arranged to have the sheet of flexible material, preferably kraft paper, between the stiff plate-like parts and the inner surface of the lateral walls in the state of use of the box casing. This arrangement of the corner elements has proven to have a significant positive effect for reinforcing the box casing in the corners.

According to another embodiment of the invention the box casing is provided with at least four corner elements, each corner element has in a flat state an elongated groove defined by the central section of the flexible sheet and lateral edge surfaces of the stiff plate-like parts extending along said central section at opposite sides thereof, two first corner elements have a said groove with a cross-sectional shape, preferably rectangular shape, allowing these corner elements to be transferred between the flat state, in which both stiff plate-like parts extend in the same plane, and a completely folded state in which the plate-like parts have been mutually pivoted substantially 180° around the flexible portion so as to extend at least substantially in parallel with each other, at least two second corner elements have a said groove with a cross-sectional shape, preferably triangular shape, allowing these corner elements to be transferred between the flat state and an angled state in which the plate-like parts have been mutually pivoted substantially 90° around the flexible portion, and further pivoting movement of the plate-like parts is obstructed by contact between the lateral edge surfaces thereof, so as to extend at least substantially perpendicularly to each other, and each first corner element is succeeded by a second corner element as seen along the circumference of the box casing.

This structure and configuration of the corner elements allow the lateral walls of the box casing to be folded on top of each other to a flat package by transferring the two first corner elements to the completely folded state and the second corner elements to the flat state. Provided with such corner elements the lateral walls of a box casing may be stored and transported as a flat package before use, the box casing is quickly and easily assembled before loading and transport, and thereafter disassembled when unloaded without any fastening means, tools or loose parts. At the same time, the reinforcing effect of the corner elements in said state of use of the box casing is optimized due to the structure of the second corner elements.

According to another embodiment of the invention the stiff plate-like parts of each said corner element are made of a straw board material. Such a material is due to its strength, durability and moisture resistance very suitable for forming the stiff plate-like parts. Furthermore, it is environmentally friendly and is possible to recycle as paper, which is a common main material for box casings of this type.

According to another embodiment of the invention the flexible portion of each said corner element is made of a paper or textile material, preferably kraft paper.

According to another embodiment of the invention the lateral walls are made of corrugated paper.

According to another embodiment of the invention each member is made of corrugated paper.

According to another embodiment of the invention the box casing is intended to be used for transport of goods.

According to another embodiment of the invention the box casing further comprises a bottom member and a lid so as to form a transport box.

According to another embodiment of the invention the box casing has a load volume of at least 50 litres, at least 100 litres, at least 250 litres, at least 500 litres, preferably at least 1000 litres.

Further advantages as well as advantageous features of the invention will appear from the following description of an embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

With reference to the appended drawings, below follows a specific description of an embodiment of the invention cited as an example.

In the drawings:

FIG. 1 is perspective view from above of a box casing according to an embodiment of the invention in a state of use,

FIG. 2 is a partly exploded perspective view from above of the box casing shown in FIG. 1, including enlarged views of two upper corners of the box casing,

FIG. 3 is a perspective view from above of a corner element of the box casing shown in FIG. 1 in a flat state,

FIG. 4 is a view showing a first step of a method of assembling the lateral walls of the box casing shown in FIG. 1,

FIG. 5 is a view showing a second step of said assembly method,

FIG. 6 is a view showing a third step of said assembly method,

FIG. 7 is a view showing a fourth step of said assembly method,

FIG. 8 is a view showing a fifth step of said assembly method,

FIG. 9 is a view showing a sixth step of said assembly method,

FIG. 10 is a view showing a seventh step of said assembly method,

FIG. 11 is a view showing an eighth step of said assembly method,

FIG. 12 is a view showing a ninth step of said assembly method, and

FIG. 13 is a perspective view from above showing the lateral walls of the box casing shown in FIG. 1 assembled and folded as a flat package.

DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

A box casing 1 according to an embodiment of the invention is illustrated in the appended FIGS. 1-13 and will now be described while at the same time making reference to all these figures.

The box casing 1 is a transport box intended to be used within the field of commercial logistics, such as for storing of goods in a warehouse, for transport of components between different parties in a production chain or for transport of products from a manufacturer to a store. Such box casings as intended have a load volume of at least 50 litres, but most commonly between 1000 and 2000 litres.

The box casing 1 has four lateral walls 2, a bottom member 3 and a lid 4 which are all made of corrugated paper. The bottom member and lid are however not essential components of the box casing, but this could be used directly on a pallet without further bottom member and lid, as one example.

The box casing 1 further comprises, for each inner corner of the box casing defined by two adjacent said lateral walls 2, a corner element 5 configured to be arranged in the respective inner corner so as to stiffen and strengthen the box casing in a state of use thereof, i.e. in an assembled state as seen in FIG. 1.

Each corner element 5 comprises two stiff plate-like parts 6, in the form of elongated boards of a straw board material, interconnected by a flexible portion 7 which is part of an elongated sheet of kraft paper. More specifically, the two stiff plate-like parts are secured to the sheet by an adhesive at a distance to each other on opposite sides of a longitudinal central section of the sheet in such a way that a channel-like space, or groove 8, is defined by lateral edge surfaces 9 of the plate-like parts 6 and the central section of the sheet, which central section of the sheet constitutes the flexible portion 7 of the respective corner element 5. Accordingly, the flexible portion of a corner element hingedly connects the stiff plate-like parts thereof to each other. The flexible portion and stiff plate-like parts of each corner element could however also be made in one piece by the same material, in which case the plate-like parts are substantially thicker portions than the flexible portion.

A straw board material is made mainly of straw glued together by straw lignin under heat and pressure. A board made of this material has corresponding bending strength and moisture resistance as a poplar plywood board, but may be recycled as paper. Hence, the straw board material contained in the corner elements 5 of the box casing 1 is excellent for providing a box casing with sufficient strength while at the same time being environmentally friendly.

The adhesive used for securing different parts of the box casing 1 to each other, such as for securing the stiff plate-like parts 6 to the sheet of kraft paper constituting the flexible portion 7 of a corner element 5, is an adhesive suitable to be recycled with paper and which contains no toxins or harsh chemicals. Such an adhesive may be based on corn starch, as one example.

The box casing 1 further comprises an arrangement configured to hold the corner elements 5 in the respective inner corners of the casing in such a way that each plate-like part 6 of a corner element is arranged internally of a separate one of two adjacent lateral walls 2, which together define an inner corner, while extending along the corner from a bottom region to a top region of the respective wall.

The arrangement comprises for each lateral wall 2 associated with a corner element 5, for each corner element, at the bottom region as well as at the top region of the wall a member 10 attached to the wall, which members are configured to keep the corner elements 5 in place at the inner corners of the casing 1 in the state of use thereof. Accordingly, each lateral wall defining at least one inner corner provided with a corner element 5 is provided with at least one such member at the bottom region of the wall and one member at the top region of the wall, for keeping that corner element in place. A lateral wall 2 defining two inner corners provided with corner elements 5 (i.e. all four walls of the box casing shown in the drawings) is provided with one such member 10 at the bottom region of the wall and one member at the top region of the wall for each of the two corner elements. However, one and the same member could extend along the entire, or substantially the entire, length of a lateral wall, from one inner corner of the casing to another, (which is the case by all members shown in the drawings) and then be associated to both corner elements associated with that wall.

Each said member 10 is an integral part of the respective wall 2, and more specifically, each member is a flap of corrugated paper extending from the top 11 or bottom 12 border of the casing 1 and having a plurality of mutually foldable plate-like sections 13-16, which mutual foldability is provided by crease lines.

Each member 10 has a first section 13 located furthest away from the top 11 or bottom 12 border of the box casing 1 in an unfolded flat state of the members (see FIG. 4) and a second section 14 located between the first section and the top or bottom border in said flat state. Each member further has a third section 15 interconnecting the second section and the top or bottom border of the casing, and a fourth section 16 interconnecting the first and second sections.

The first section 13 of each member 10 extends along the entire length, i.e. along the entire top or bottom border, of the lateral wall 2 to which the member is attached. The second 14 and third 15 sections of each member have the same length and are shorter than the first section. The fourth section 16 of each member is shorter than the second and third sections. The first 13 and second 14 sections of each member have the same width, and the third 15 and fourth 16 sections have the same width, which is smaller than that of the first and second sections. All sections of each member are centered along the length of the lateral wall to which the member is attached, so that a section with a greater length extends equally far past both outer edges of a section with a relatively smaller length, as seen in the direction of longitudinal extension of the top and bottom borders.

Each member 10 is in the state of use, i.e. assembled state, of the box casing 1 configured to be folded into the inner space 17 of the casing defined by the lateral walls 2 and towards an inner surface 18 of the wall to which it is attached to trap a stiff plate-like corner element part 6 in each of the two inner corners associated with this wall by a respective end portion of the member, between this member and said inner surface.

In a state of trapping a plate-like part 6 of a corner element 5 arranged in an inner corner of the casing 1, the third section 15 of a said member 10 is folded from a top border 11 or a bottom border 12 of the casing inwardly by 90° or substantially 90° to form a stop to prevent said stiff plate-like corner element part 6 to escape in the direction of the extension of the corner. The extension of said third section inwardly is approximately the same as the thickness of the stiff plate-like corner element part. The second section 14 of the member is folded from the third section to extend in said inner space 17 of the casing 1 substantially in parallel with the-inner surface 18 of the lateral wall 2 to which the member is attached. The fourth section 16 is folded from said second section towards said inner wall surface 18 and the first section 13 is folded from the fourth section to extend oppositely to the second section 14 along said inner wall surface towards said top border 11 or bottom border 12 of the casing 1. The third 15 and fourth 16 sections of the member have substantially the same width as seen in a direction perpendicularly to the inner wall surface 18.

The member 10 is in this way configured to have the first section 13 folded to be arranged between the inner wall surface 18 of the wall 2 and the stiff plate-like corner element part 6 and the second section 14 folded towards said inner wall surface to hold said corner element part trapped between this second section and said inner surface 18 so as to lock said first section 13 of the member between the inner wall surface and the corner element part 6 and by that lock the member in the state of trapping the corner element part. The trapping configuration of each member 10 is further described below, in a method for creating the box casing 1.

A method for creating, by assembling the lateral walls of, the box casing 1 is now to be described while making reference to FIGS. 3-13. A flat sheet of corrugated paper provided with crease lines is provided (see FIG. 4), which will form the four lateral walls 2 of the box casing, including said members 10 attached to the top 11 and bottom 12 borders thereof, i.e. two members for each lateral wall. Furthermore, four corner elements 5 are provided in a flat unfolded state (see FIG. 3).

At first, each member 10 is folded along all crease lines thereof, starting for instance with folding the third section 15 from the top 11 or bottom 12 border of the casing 1 to be created, as is seen in FIG. 5. The first sections 13 of all members attached to the top border 11 of the box casing to be created are formed together in one piece and defined by crease lines on that piece. In the same way are the first sections 13 of all members attached to the bottom border 12 of the box casing to be created formed together in one piece and defined by crease lines on that piece. The members at the top border are thus interconnected by the first sections 13 thereof which simplifies the folding of said members as these are folded simultaneously. The same applies to the members at the bottom border.

It is seen in FIG. 6 that the fourth section 16 of each member has been folded from the second section 14 and further that the first section 13 has been folded from the fourth section. It is seen in

FIG. 7 that the second section 14 of each member finally is folded from the third section 15 so that the first section 13 is placed against an inner wall surface 18 of the casing 1 to be created to extend therealong from the fourth section 16 towards the top 11 or bottom 12 border of the casing. After this step are all members 10 folded along all crease lines thereof.

Then, the four corner elements 5 are arranged along the crease lines between the lateral walls 2 by firstly inserting one plate-like part 6 of each corner element in a “pocket” 20 defined between two adjacent members 10 at the top 11 and bottom 12 borders of the casing 1 to be created (see FIG. 7) and sliding this plate-like part on the first section 13 and under the second section 14 of one of said members towards an outer edge 19 of the fourth section 16 of that member defining a stop for the plate-like part (see FIG. 8) in the direction of extension of the top or bottom border. In this position, the other plate-like part 6 of the corner element 5 may be lowered down into the pocket (see FIG. 9) and the corner element is then slid towards the other of said members and under the secand section 14 thereof so as to be centered in the pocket at the top 11 and bottom 12 borders of the casing (see FIG. 10).

As is seen in the drawings, each corner element 5 is placed with the kraft paper against the inner surfaces 18 of the associated lateral walls 2, i.e. between the stiff plate-like parts 6 and the inner surfaces. This arrangement of the corner elements has proven to give a significant positive reinforcing effect on the box casing 1.

As is best seen in FIG. 10, the box casing 1 is provided with two types of corner elements 5, namely first 5 a and second 5 b corner elements. The only difference between them is the cross-sectional shape of said groove 8, and more specifically the structure of the lateral edge surfaces 9 of the plate-like parts 6 extending along the central section of the respective element at opposite sides thereof.

The first corner elements 5 a have a groove 8 with a rectangular cross-sectional shape (area) allowing these corner elements to be transferred between a flat state (see for instance FIG. 10), in which both stiff plate-like parts 6 extend in the same plane, and a completely folded state (see FIG. 13) in which the plate-like parts have been mutually pivoted substantially 180° around the flexible portion 7 so as to extend at least substantially in parallel with each other.

The second corner elements 5 b have a groove 8 with a triangular cross-sectional shape (area) allowing these corner elements to be transferred between the flat state (see for instance FIG. 10) and an angled state (see FIG. 2) in which the plate-like parts 6 have been mutually pivoted substantially 90° around the flexible portion 7, and further pivoting movement of the plate-like parts is obstructed by contact between the lateral edge surfaces 9 thereof, so as to extend at least substantially perpendicularly to each other. These second corner elements 5 b provide the associated corners and thereby the box casing 1 with an excellent strength and stability due to the limited mutual moveability of the stiff plate-like parts 6 thereof.

The corner elements 5 are arranged in such a way that each first corner element 5 a is succeeded by a second corner element 5 b as seen along the circumference of the box casing 1 to be created, which means that every other corner element is a first corner element and every other is a second corner element by a box casing with four lateral walls 2. These different structures and the arrangement of the corner elements make a strong box casing which is still easily folded to a flat package.

When the corner elements 5 are properly arranged, the two first corner elements 5 a are transferred towards the completely folded state by folding the outermost lateral walls 2 towards each other (see FIGS. 11-12). A second corner element 5 b partly protruding past an outer edge of one of said outermost lateral walls is then inserted between the second sections 14 of the top and bottom members 10 and the inner surface 18 of the other said lateral wall (see FIG. 12). Said other lateral wall is provided with a flap 21 along an outer edge thereof, which is placed over an outer surface of the lateral wall with the protruding corner element, and secured thereto by securing means, such as staples (see FIG. 13). Hereby, a flat package containing the assembled lateral walls 2 and the corner elements 5 of the box casing 1 is provided, as one unit.

When the lateral walls 2 of the box casing 1 are erected (see FIG. 2), each plate-like part 6 of each corner element 5 is trapped along a respective inner corner by a said member 10 at the top border 11 of the casing and a said member at the bottom border 12 of the casing. More specifically, the corner element part 6 locks the first section 13 of each said member between said part and an inner surface 18 of the associated lateral wall 2 which in turn locks the second section 14 in a state of trapping the corner element part. Accordingly, the stiff plate-like corner element part 6 is prevented from moving in a direction away from the inner wall surface 18 by the second section 14 of the member 10 and prevented from moving along the extension of the associated inner corner by the third section 15 of the members at the top and bottom borders of the casing. At the same time, the members are locked by the corner element which gives a very stable structure. Furthermore, the fact that the first sections 13 of all members 10 at the top border 11 of the casing, as well as the first sections of all members at the bottom border 12 of the casing, are interconnected implies an excellent locking of all these members in said state of trapping the corner elements as the first sections are prevented from being unfolded at the inner corners by themselves.

Hence, a very strong and durable box casing 1 which is reinforced along all borders 11, 12 (by the members 10) and corners (by the corner elements 5) is provided, and the arrangement with the members ensure that the corner elements are properly held in the inner corners of the casing during use thereof.

The box casing 1 is intended to be delivered to a customer as three separate parts, namely a bottom member 3, a lid 4 and—in the form of a flat package—the lateral walls 2 provided with corner elements 5 (see FIG. 13). The transport and delivery of the flatly packed box casing in a condition basically ready-for-use is made possible through the configuration of the corner elements 5 and the locking thereof by the members 10 at the lateral walls.

The flat package with lateral walls 2 and corner elements 5 comprises four corner elements, of which two diagonally opposing corner elements are second corner elements 5 b in the flat state and the other two diagonally opposing corner elements are first corner elements 5 a in the completely folded state. The box casing 1 is quickly assembled before use by simply unfolding the package with the already interconnected lateral walls 2 by pulling one of the two second corner elements 5 b in the flat state away from the other until the inner corners of the box casing to be created are right-angled, and then placing the walls on the bottom member 3 and the lid 4 on top of the walls. The bottom member and the lid comprise securing means for at least partially securing these components with respect to the walls, in the form of rims 22 protruding from the peripheral edge regions thereof configured for form-fitted interlocking with the lateral walls 2.

For disassembling the empty box casing 1 to for instance be stored or sent back to a logistics provider, the lid 4 is firstly removed from the lateral walls 2 and these are then lifted away from the bottom member 3. Thereafter, the interconnected lateral walls 2 are folded to a flat package by pushing the two diagonally opposite corners provided with second corner elements 5 b together until the walls 2 collapse so that the two first corner elements 5 a obtain the completely folded state and the two second corner elements 5 b obtain the flat state. Hence, assembly and disassembly of the box casing la is done quickly and easily without the need of tools or separate fastening means thanks to the advantageous structure thereof.

The invention is of course not in any way restricted to the embodiments thereof described above, but many possibilities to modifications thereof will be apparent to a person with ordinary skill in the art without departing from the scope of the invention as defined in the appended claims.

The box casing may comprise further reinforcing components than the corner elements described, such as boards of straw board arranged at the center of one or more lateral walls extending between a top and bottom region thereof and secured by the arrangement in a similar way as the corner elements.

A box casing is in this disclosure to be interpreted as a box of any shape or a part of such a box defining a space suitable for accommodating objects to be stored or transported in the box casing.

Accordingly, a box casing may be constituted by an arbitrary number of, however at least four, lateral walls and optionally one or more bottom members and/or lids.

The flexible portion of a said corner element is to be considered as being the intermediate part between two said stiff plate-like parts of that corner element, which flexible portion is configured to function as a hinge between said two stiff plate-like parts. The flexible portion may comprise one or more flexible material layers such as sheets of paper or fabric, a net structure or a plurality of elongated flexible elements, such as strings or paper strips, as a few examples. Each stiff plate-like part of each corner element may independently have a different shape and appearance than described above and shown in the drawings, such as having the appearance of a grill. It is of course also possible that the plate-like parts are made of another material than straw board, such as wood or a paper based material, although straw board is preferred due to its advantageous properties as described above. 

1. A box casing (1) having at least four lateral walls (2), which box casing (1) comprises, for a majority of, preferably each, inner corner of the box casing (1) defined by two adjacent said lateral walls (2), a corner element (5) having two stiff plate-like parts (6) interconnected by a flexible portion (7), each plate-like part (6) being in a state of use of the box casing (1) configured to be arranged internally of a separate one of two adjacent lateral walls (2) while extending along the corner from a bottom region to a top region of the wall, the box casing (1) having an arrangement configured to hold the corner elements (5) in the respective inner corners so as to stiffen the box casing (1) in said state of use thereof, wherein said arrangement comprises for each lateral wall (2) associated with a corner element (5), for each corner element (5), at the bottom region as well as at the top region of the wall (2) a member (10) attached to the wall (2) and folded into the inner space (17) of the casing (1) defined by the walls (2) and towards an inner surface (18) of the wall (2) to trap said stiff plate-like corner element part (6) between this member (10) and said inner surface (18).
 2. A box casing (1) according to claim 1, wherein each said member (10) is an integral part of the respective wall (2) to be folded into the inner space (18) of the casing (1) from a top border (11) or a bottom border (12) of the casing (1).
 3. A box casing (1) according to claim 2, wherein each said member (10) has a first section (13) folded to be arranged between an inner wall surface (18) and a respective stiff plate-like corner element part (6) and a second section (14) folded towards said inner wall surface (18) to hold said corner element part (6) trapped between this second section (14) and said inner surface (18) so as to lock said first section (13) of the member (10) between the inner wall surface (18) and the corner element part (6) and by that lock the member (10) in a state of trapping the corner element part (6).
 4. A box casing (1) according to claim 3, wherein each said member (10) comprises a third section (15) folded from a top border (11) or a bottom border (12) of the casing (1) inwardly by 90° or substantially 90° to form a stop to prevent said stiff plate-like corner element part (6) to escape in the direction of the extension of the corner, and the second section (14) is folded from the third section (15) to extend in said inner space (17) of the casing (1) substantially in parallel with said inner wall surface (18).
 5. A box casing (1) according to claim 4, wherein the extension of said third section (15) inwardly is approximately the same as the thickness of said stiff plate-like corner element part (6).
 6. A box casing (1) according to claim 4, wherein said first (13) and second (14) sections of each member (10) are interconnected by a fourth section (16) folded from said second section (15) towards said inner wall surface (18) and from which said first section (13) is folded to extend oppositely to the second section (14) along said inner wall surface (18) towards said top border (11) or bottom border (12) of the casing
 7. A box casing (1) according to claim 6, wherein said third (15) and fourth (16) sections of each said member (16) have substantially the same width as seen in a direction perpendicularly to the respective inner wall surface (18).
 8. A box casing (1) according to claim 3, wherein the first sections (1) of all said members (10) at the top (11) and bottom (12) border of the casing (1), respectively, are formed together in one piece configured to, in said state of use, be folded in the corners of the box casing (1) to extend along the entire inner circumference thereof.
 9. A box casing (1) according to claim 2, wherein each member (10) is a flap extending from the top (11) or bottom (12) border of the casing (1) and having a plurality of mutually foldable plate-like sections (13-16).
 10. A box casing (1) according to claim 1, wherein each member (10) is configured to extend along the entire, or substantially the entire, length of a respective lateral wall (2), from one inner corner of the casing (1) to another, and by that to trap said stiff plate-like corner element part (6) by each of two end portions of the member (10) in said state of use of the casing (1).
 11. A box casing (1) according to claim 1, wherein each corner element (5) comprises an elongated sheet of a flexible material and that the two stiff plate-like parts (6) are secured to the sheet by an adhesive at a distance to each other on opposite sides of a longitudinal central section of the sheet, which central section constitutes the flexible portion (7) of the corner element (5).
 12. A box casing (1) according to claim 11, wherein each corner element (5) is configured to be arranged to have the sheet of flexible material, preferably kraft paper, between the stiff plate-like parts (6) and the inner surface (18) of the lateral walls (2) in the state of use of the box casing (1).
 13. A box casing (1) according to claim 11, wherein the box casing (1) is provided with at least four corner elements (5), each corner element (5) in a flat state has an elongated groove (8) defined by the central section of the flexible sheet and lateral edge surfaces (9) of the stiff plate-like parts (6) extending along said central section at opposite sides thereof, that two first corner elements (5 a) have said groove (8) with a cross-sectional shape, preferably rectangular shape, allowing these corner elements (5 a) to be transferred between the flat state, in which both stiff plate-like parts (6) extend in the same plane, and a completely folded state in which the plate-like parts (6) have been mutually pivoted substantially 180° around the flexible portion (7) so as to extend at least substantially in parallel with each other, at least two second corner elements (5 b) have said groove (8) with a cross-sectional shape, preferably triangular shape, allowing these corner elements (5 b) to be transferred between the flat state and an angled state in which the plate-like parts (6) have been mutually pivoted substantially 90° around the flexible portion (7), and further pivoting movement of the plate-like parts (6) is obstructed by contact between the lateral edge surfaces (9) thereof, to extend at least substantially perpendicularly to each other, and each first corner element (5 a) is succeeded by a second corner element (5 b) as seen along the circumference of the box casing (1).
 14. A box casing (1) according to claim 1, wherein the box casing (1) further comprises a bottom member (3) and a lid (4) so as to form a transport box.
 15. A box casing (1) according to claim 5, wherein said first (13) and second (14) sections of each member (10) are interconnected by a fourth section (16) folded from said second section (15) towards said inner wall surface (18) and from which said first section (13) is folded to extend oppositely to the second section (14) along said inner wall surface (18) towards said top border (11) or bottom border (12) of the casing (1).
 16. A box casing (1) according to claim 17, wherein the first sections (1) of all said members (10) at the top (11) and bottom (12) border of the casing (1), respectively, are formed together in one piece configured to, in said state of use, be folded in the corners of the box casing (1) to extend along the entire inner circumference thereof.
 17. A box casing (1) according to claim 7, wherein the first sections (1) of all said members (10) at the top (11) and bottom (12) border of the casing (1), respectively, are formed together in one piece configured to, in said state of use, be folded in the corners of the box casing (1) to extend along the entire inner circumference thereof.
 18. A box casing (1) according to claim 6, wherein the first sections (1) of all said members (10) at the top (11) and bottom (12) border of the casing (1), respectively, are formed together in one piece configured to, in said state of use, be folded in the corners of the box casing (1) to extend along the entire inner circumference thereof.
 19. A box casing (1) according to claim 5, wherein the first sections (1) of all said members (10) at the top (11) and bottom (12) border of the casing (1), respectively, are formed together in one piece configured to, in said state of use, be folded in the corners of the box casing (1) to extend along the entire inner circumference thereof.
 20. A box casing (1) according to claim 4, wherein the first sections (1) of all said members (10) at the top (11) and bottom (12) border of the casing (1), respectively, are formed together in one piece configured to, in said state of use, be folded in the corners of the box casing (1) to extend along the entire inner circumference thereof. 